The invention relates generally to video signals, and more particularly to detection of copy protection included in video signals.
Video signals may originate from a number of different sources including a videocassette recorder (VCR), digital video disc (DVD) player, etc. In order to prevent. users from making unauthorized copies or derivations of protected works included in video signals, copy protection techniques have been developed that prevent such video signals from being recorded on standard recording devices such as VCRs. These copy protection techniques allow the signal to be utilized for display purposes, but prevent recording devices such as VCRs from accurately recording all of the information in the video stream.
As video graphics processing circuits continue to evolve, additional capabilities that allow video signals to be provided to a number of different outputs of the circuits exist. In such systems, the video signals are often broken down into their component parts and stored in memory. When video signals are broken down in such a manner, the techniques utilized to implement copy protection in the video signal are often defeated.
In some instances, the output data stream of the video processing circuitry is not provided to a device capable of recording the information included in the video signal. In such instances, defeating the copy protection included in the video signal is not an issue. However, if the video signal is reconstructed from the component data and provided to an output that may be connected to a VCR or other recording capable device, the video graphics circuitry has effectively removed the copy protection from the video stream. As such, this allows for unauthorized copies or derivations to be produced, which is undesirable.
Therefore, a need exists for a method and apparatus that is able to detect copy protection included in a video graphics stream and ensure that when it is present unauthorized copies or derivations of information included in the video stream are not permitted.